System, a control unit and a method for controlling capacitors in the system in an at least partly electrical driven vehicle

Abstract

A system for controlling capacitors comprised in an at least partly electrical driven vehicle. The system comprises a converter comprising a first capacitor connected to a first side of a three-phase bridge. The system comprises a third capacitor adapted to be controlled, via a first switch, to be either connected in parallel to or disconnected from the first capacitor. The system is adapted such that, when the converter is activated and is initiated to start operating or is currently operating, the first switch is in a closed position such that the third capacitor is connected. The system is further adapted such that, when the converter is inactivated and is not in operation, the first switch is in an open position such that the third capacitor is disconnected.

1 . A system for controlling capacitors comprised in an at least partly electrical driven vehicle, the system comprises:
 a converter comprising a first capacitor connected to a first side of a three-phase bridge;   a third capacitor adapted to be controlled, via a first switch, to be either connected in parallel to or disconnected from the first capacitor,   wherein the system is adapted such that, when the converter is activated and is initiated to start operating or is currently operating, the first switch ( 216   a ) is in a closed position such that the third capacitor is connected,   and wherein the system is further adapted such that, when the converter is inactivated and is not in operation, the first switch is in an open position such that the third capacitor is disconnected.   
     
     
         2 . The system according to  claim 1 , wherein a first pre-charge circuit is connected between the third capacitor and the first switch, and wherein the first pre-charge circuit is adapted to pre-charge the third capacitor. 
     
     
         3 . The system according to  claim 1 , wherein the third capacitor is located at one of the following positions:
 1) inside the converter;   2) outside the converter and with connection to poles of the power supply and after an inductive filter;   3) outside the converter and with connection to the poles of the power supply and before the inductive filter.   
     
     
         4 . The system according to  claim 1 ,
 wherein the converter comprises a second capacitor connected to a second side of the three-phase bridge which is opposite of the first side,   wherein a fourth capacitor is adapted to be controlled, via a second switch, to be either connected in parallel to or disconnected from the second capacitor,   wherein system is adapted such that, when the converter is activated and is initiated to start operating or is currently operating, the second switch is in a closed position such that the fourth capacitor is connected,   wherein system is further adapted such that, when the converter is inactivated and is not in operation, the second switch is in an open position such that the fourth capacitor is disconnected,   wherein the third capacitor and the fourth capacitor are located at opposite sides of the system.   
     
     
         5 . The system according to  claim 4 , wherein a second pre-charge circuit is connected between the fourth capacitor and the second switch, and wherein the second pre-charge circuit is adapted to pre-charge the fourth capacitor. 
     
     
         6 . The system according to  claim 4 , wherein the fourth capacitor is located at a position on the opposite side that corresponds to the position of the third capacitor. 
     
     
         7 . A method for performed by a control unit for controlling capacitors in a system in an at least partly electrical driven vehicle, the system comprises:
 a converter comprising a first capacitor connected to a first side of a three-phase bridge;   a third capacitor adapted to be controlled, via a first switch, to be either connected in parallel to or disconnected from the first capacitor, the method comprises:
 detecting that the converter is activated and is initiated to start operating; 
   when it has been detected that the converter is activated and is initiated to start operating, triggering the first switch to enter a closed position such that third capacitor is connected to the first capacitor before the converter starts operating;   detecting that the converter is inactivated and is not in operation; and   when it has been detected that the converter is inactivated and is not in operation, triggering the first switch to enter an open position such that the third capacitor is disconnected from the first capacitor.   
     
     
         8 . The method according to  claim 7 , wherein a first pre-charge circuit is connected between the third capacitor and the first switch, and wherein the method comprising:
 after the first switch has been triggered to enter the closed position, detecting that the third capacitor is charged;   when it has been detected that the third capacitor is charged, triggering inactivation of the first pre-charge circuit.   when it has been detected that the converter is inactivated and is not in operation, triggering activation of the first pre-charge circuit.   
     
     
         9 . The method according to  claim 7 , wherein the third capacitor is located at one of the following positions:
 1) inside the converter;   2) outside the converter and with connection to poles of the power supply and after an inductive filter;   3) outside the converter and with connection to the poles of the power supply and before the inductive filter.   
     
     
         10 . The method according to  claim 7 ,
 wherein the converter comprises a second capacitor connected to a second side of the three-phase bridge which is opposite of the first side,   wherein a fourth capacitor is adapted to be controlled, via a second switch, to be either connected in parallel to or disconnected from the second capacitor,   wherein the method comprises:   when it has been detected that the converter is activated and is initiated to start operating, triggering the second switch to enter a closed position such that the fourth capacitor is connected to the second capacitor before the converter starts operating; and   when it has been detected that the converter is inactivated and is not in operation, triggering the second switch to enter an open position such that the fourth capacitor is disconnected from the second capacitor.   
     
     
         11 . The method according to  claim 10 , wherein a second pre-charge circuit is connected between the fourth capacitor and the second switch, and wherein the method comprises:
 after the second switch has been triggered to enter the closed position, detecting that the fourth capacitor is charged; and   when it has been detected that the fourth capacitor is charged, triggering inactivation of the second pre-charge circuit; and   when it has been detected that the converter is inactivated and is not in operation, triggering activation of the pre-charge circuit.   
     
     
         12 . The method according to  claim 11 , wherein the fourth capacitor is located at a position on the opposite side that corresponds to the position of the third capacitor. 
     
     
         13 . A control unit for controlling capacitors in a system in an at least partly electrical driven vehicle, the control unit being configured to perform the steps of the method according to  claim 7 . 
     
     
         14 . A vehicle comprising a system according to  claim 1 . 
     
     
         15 . A computer program comprising program code means for performing the steps of  claim 7  when the computer program is run on a computer. 
     
     
         16 . A computer readable medium carrying a computer program comprising program code for performing the steps of  claim 7  when the computer program is run on a computer.